New Pier Design Shows Promise to Protect Bridges from Blast and Earthquake Forces

Experimental test setup

The bridge pier design was subjected to large blast forces

The bridge pier deformed, but did not fail, after the blast

Bridges support important economic lifelines for cities throughout the U.S. As with other critical components of the infrastructure, they are vulnerable to a variety of threats, including from terrorist attacks. MCEER is investigating how technologies developed to prevent damage due to earthquakes can be adapted for protection against other threats.

One project currently underway is the development of a new design for bridge
piers. The design, intended for use in small and medium-sized bridges, uses
corrosion resistant steel tubes filled with concrete, but without reinforcing
bars. The steel and concrete bind together, forming a composite structure,
which provides the piers with superior strength and ductility. Additional
structural shapes are imbedded in the concrete footing and pier cap to resist
the large flexural forces that can develop at the base and top of the bridge
piers.

The design was field tested this past summer at the U.S. Army Corps
of Engineers Research Facility in Vicksburg, Mississippi. Two ¼-scale prototype bridge bents were subjected to blast forces similar to those corresponding to a credible terrorist threat for this kind of bridge. Following the testing, the piers showed permanent flexural deformations but they did not suffer any significant damage.

The bridge pier design is intended for use in the construction of new bridges,
but future research will focus on development of retrofit variations for
existing bridges. Detailed analysis is underway using data collected as part
of this test program, to develop design recommendations and to calibrate
and investigate the effectiveness of more advanced analytical models.

The
design was developed by Michel Bruneau, professor in the Department of Civil,
Structural and Environmental Engineering at the University at Buffalo. UB
graduate student Shuichi Fujikara participated in the testing, and post-doctoral
research associate Diego Lopez Garcia contributed to the research. The research
is part of MCEER's Highway Project, funded by the Federal Highway Administration.